Efeitos da aplicação de óleos essenciais à dieta de tilápia-do-nilo (Oreochromis niloticus)

Abstract

Global population growth poses challenges to sustainable food production, highlighting aquaculture as a strategic alternative for supplying animal protein. In this context, Nile tilapia (Oreochromis niloticus) stands out due to its high adaptability to intensive farming systems, rapid growth, and wide commercial acceptance. However, the intensification of production favors the emergence of diseases and the excessive use of antibiotics, driving the search for natural additives capable of improving fish performance and health. Thus, essential oils emerge as promising additives due to their antimicrobial, antioxidant, and immunomodulatory properties. The present study evaluated the palatability and the zootechnical and histological effects of dietary supplementation with different essential oils for juvenile Nile tilapia under controlled laboratory conditions. The essential oils of Cassia Cinnamon (Cinnamomum cassia), Lemongrass (Cymbopogon flexuosus), Eucalyptus (Eucalyptus staigeriana), and Oregano (Origanum vulgare) were individually supplemented at concentrations of 0.1, 1, and 10 mL/kg of commercial feed. Zootechnical performance was evaluated through Mean Weight, Total Weight Gain (TWG), Apparent Feed Conversion Ratio (FCR), and Survival, while palatability was assessed through feed intake tests and latency to the first feeding attack. The results demonstrated a positive effect of supplementation at intermediate concentrations (1 mL/kg), reinforcing the existence of an optimal inclusion range. Cassia Cinnamon and Lemongrass showed the greatest growth increments, with estimated additional gains of approximately 1.3 g and 1.2 g compared to the control group, respectively. Cassia Cinnamon presented the best overall productive performance, with greater zootechnical stability and absence of relevant histological alterations, whereas Lemongrass promoted growth enhancement associated with mild gastric alterations compatible with adaptation to dietary stimulus. Oregano stood out for its functional effects on palatability and feeding behavior, while Eucalyptus showed more discrete effects, mainly related to the initial acceptance of the diets. Overall, the essential oils proved to be biologically safe, maintaining high survival rates (92.5–100%) with no adverse effects on water quality or tissue integrity. It is concluded that the evaluated essential oils present potential as functional and attractant-palatability additives in Nile tilapia farming, especially at intermediate concentrations, highlighting Cassia Cinnamon as a promoter of productive performance, Lemongrass for its growth-stimulating potential associated with adaptive responses of the digestive tract, and Oregano as a modulator of feeding behavior and physiological responses in fish.